1. Field
The present disclosure relates generally to the field of video processing and, more specifically, to techniques for reducing bus traffic of a texture decoding module in a video decoder.
2. Background
The amounts of digital information contained in video data are massive and tend to increase along with advances in performance of video cameras. Processing of the video data places large demands on memory, computational, bandwidth, and power resources of video-enabled devices and, in particular, battery-powered wireless communication devices such as cellular phones, personal digital assistants (PDAs), laptop computers, and the like.
In video processing systems compliant with Motion Picture Expert Group (MPEG-4)/VC-1/H.264 standards, the coefficients of each macroblock of a bitstream are described using 384 16-bit words. In a video decoder, a video bitstream is inputted to an ARM or DSP processor to perform syntax element parsing, and the decoded residual data is un-zigzagged to define, in a raster-scan order, 384 quantized coefficients for each macroblock of the bitstream. The quantized coefficients are then inputted to a Texture Decoding hardware (HW) module in a Pixel Processor accelerator of a video processor.
A texture decoding process includes procedures such as de-quantization, inverse transform to form residual macroblocks, and adding motion compensated macroblocks to generate reconstructed macroblocks. For a display rate of WVGA at 30 frames per second, 384 coefficients per macroblock inputted to the Texture Decoding module generate 104 MBps data traffic. Specifically, when the ARM or DSP writes the quantized coefficient data to external memory, the Texture Decoding HW module fetches the data back, and write cache-miss produces a doubled amount of the bus traffic. Although video compression significantly reduces redundancy of compressed video data, such processing techniques may decrease overall performance and consumer-critical characteristics (for example, battery life, talk time, etc.) of the wireless communication devices.
There is therefore a need in improved techniques for reducing bus traffic during texture decoding in macroblocks of video bitstreams.